/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.factory.parsing;

import org.springframework.beans.BeanMetadataElement;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * Representation of an alias that has been registered during the parsing process.
 *
 * @author Juergen Hoeller
 * @see ReaderEventListener#aliasRegistered(AliasDefinition)
 * @since 2.0
 */
public class AliasDefinition implements BeanMetadataElement {

    private final String beanName;

    private final String alias;

    @Nullable
    private final Object source;


    /**
     * Create a new AliasDefinition.
     *
     * @param beanName the canonical name of the bean
     * @param alias the alias registered for the bean
     */
    public AliasDefinition(String beanName, String alias) {
        this(beanName, alias, null);
    }

    /**
     * Create a new AliasDefinition.
     *
     * @param beanName the canonical name of the bean
     * @param alias the alias registered for the bean
     * @param source the source object (may be {@code null})
     */
    public AliasDefinition(String beanName, String alias, @Nullable Object source) {
        Assert.notNull(beanName, "Bean name must not be null");
        Assert.notNull(alias, "Alias must not be null");
        this.beanName = beanName;
        this.alias = alias;
        this.source = source;
    }


    /**
     * Return the canonical name of the bean.
     */
    public final String getBeanName() {
        return this.beanName;
    }

    /**
     * Return the alias registered for the bean.
     */
    public final String getAlias() {
        return this.alias;
    }

    @Override
    @Nullable
    public final Object getSource() {
        return this.source;
    }

}
